Centering-frame.



PATENTED AUG. 8, 1905.

' P. R. BURTON.

CENTERING FRAME; APPLICATION FILED An. 24,1905.

munzw. a, can co. PMOTO-LIYPFOGHAPNERS, wnsl-uns'rou. B. c

I UNITED STATES PATENT OFFICE.

CENTERlNG-FRAME.

Specification of Letters Patent.

Patented Aug. 8, 1905.

Application filed April 24:, 1905. Serial No. 257,226.

To all whom it may concern.-

Be it known that I, PHILIP RAY BURTON, a citizen of the United States,residing at Bakersfield, in the county of Kern and State of California,have invented new and useful Improvements in Centering-Frames, of whichthe following is a specification.

This invention is a centering device or form to be used in tunnels,sewers, culverts, shafts, and the like; and it is characterized by thefact that it is portable and may be moved along in the tunnel or otherwork for continuous operation and by the further fact that it may beexpanded or contracted to release the same from the completed sectionand to locate it for the next section.

In the accompanying drawings the invention is illustrated as applied tothe construction of a railway tunnel, and referring thereto Figure 1 isan end elevation'of the structure. Fig. 2 is an inner side elevation.

Referring specifically to the drawings, 6 indicates upright timbers, tothe top of which are joined the curved or arched timbers 7. Thesetimbers are of proper height and shape to correspond approximately tothe dimensions of the tunnel to be built. The timbers 6 on oppositesides of the frame are braced and spaced apart by horizontal timbers 8,the length of each of which is somewhat less than one-halfthe width ofthe tunnel. The timbers 6, 7, and 8 are joined and strengthened byironbrace-plates 9.

Between the ends of the horizontal timbers 8 and also between the endsof the arched timbers 7 at the crown of the arch are adjusting screws10, having right and left threads, which work in nuts 11 in oppositeends of said timbers. These act to spread or contract the formhorizontally. Removable jacks 12 are placed under the lower ends of theuprights 6.

13 indicates lagging secured to the outer sides of the timbers 6 and 7to produce the shield and form. It will be understood that there are twoor more sets of frames to which the lagging is secured.

For the purpose of moving the structure a flat-car 14E is employed,running on tracks laid in the tunnel.

In use the structure is moved along by the car to the proper position inthe unfinished tunnel and then expanded by means of the screws andlifted by means of the jacks until it reaches the proper dimensions andoccupies the proper position. Concrete filling is then run in betweenthe walls of the tunnel and the form and allowed to set. The sides arethen contracted by means of the screws 10 and the jacks 12 lowered untilthe lower crossbeams 8 rest upon the car. The structure can then bemoved along to the next section and the operation repeated.

The structure may thus be used repeatedly for continuous operation inthe building of tunnels, sewers, and the like. For brickwork the laggingmay be removable and can be built up as fast as the masonry proceeds.

What I claim as new, and desire to secure by Letters Patent, is-

A centering-frame for the purpose stated,

comprising side sections having upright and PHILIP RAY BURTON.

Witnesses: v

MATTHEW S. PLATZ, CHAS. A. DE PEW.

